Hall effect devices are becoming increasingly popular in industry for such purposes as sensing rotors of brushless motors and in other applications where the contactless sensing of moving mechanical elements is desirable. Conventional Hall effect devices have three leads. One lead is provided for the voltage supply, one lead for the ground, and one lead for the output. Thus, for conventional Hall effect devices, three connections have to be provided to the remainder of the system into which they are incorporated. Ideally, however, the number of leads and connections to a sensor should be minimized, especially in situations where space is at a premium both in the finished system and in terms of space required for assembly.
In manufacturing processes, each additional lead on a device generally comes at a cost, generally on the order of dollars per connection. In many applications, leads must be connected to a Hall effect device in a remote location and must be routed to a central location. At the central location, the other ends of the device leads must be connected to sensing and power circuitry. During the assembly of many such devices into a product, the connection costs therefor can be substantial. The connections of the lead ends at the central location often must be made to a small area on a circuit board. Each additional lead required by the device increases the difficulty in making each circuit board connection within the small area, and each additional lead increases the probability that a mistake will be made in connecting the right lead to the right location.
In the design of products such as vehicles, each Hall effect device is specified as taking up a certain volume which cannot be exceeded. This volume in turn determines the amount of contact area that the device can provide for soldering leads to it, the amount of solder that can be used, the size of the lead wires and the amount of wire insulation. For every additional lead required by the device, the specified volume gets more crowded, and contact area per lead, solder amount per lead, lead wire size and lead insulation thickness must all be scaled down. The integrity of the connections of the leads to the device consequently becomes more of a problem.
In view of the above problems, there exists a need for a Hall effect sensor with fewer leads in order to reduce the problems associated with conventional devices which have three or more leads.